1. Field of the Invention
The present invention relates to an air cooled oil cooler used for cooling a oil of an engine of a motor vehicle or the like.
2. Description of the Related Art
An air cooled oil cooler is known, which has plural tubes each consisting of a pair of plate members to be coupled and an inner fin disposed in the coupled plate members. The tubes are piled up and formed at their both side ends with a communicating hole to pass an oil among the tubes so that the oil discharged from an engine can be cooled by air flow passing through a space between the tubes while flowing in the tubes and return to the engine for avoiding its overheat.
A conventional air cooled oil cooler of this kind is disclosed in Japanese patents laying-open publication Nos. 2000-146479, Tokkaihei 11-118366, and Tokkaihei 11-72295.
This conventional air cooled oil cooler, however, encounters the following problems. Recently, there is a demand for higher output power of engines, which requires improving coolability of air cooled oil coolers. In order to meet this requirement, the number of a pile of the tubes may be increased in an oil cooler of the above prior arts, but this brings growing in size of a core of the oil cooler.
In addition, there is also a demand for reduction in an engine room according to enlargement of a passenger compartment, which requires smaller air cooled oil coolers.
It is, therefore, an object of the present invention to provide an air cooled oil cooler which overcomes the foregoing drawbacks and can improve its oil coolability with suppression of its size growing.